The invention relates to degaussing or demangetizing recording tapes which have been magnetized or recorded on, linearly along the tape; the tape is normally kept in reel form or coiled form, both before and after the recording, and it is desired to degauss or demagnetize the reel as a whole, or in bulk form and not linearly of the tape. Bulk demagnetizing as a general operation has been done before, but the present invention relates to specific apparatus and method for accomplishing that overall effect.